A direct injection engine may produce particulate matter if portions of injected fuel are not completely combusted. The particulate matter may be trapped in a filter and combusted at a later time to purge the particulate filter. However, there may be conditions when it may not be conducive to purge the particulate filter. For example, it may not be desirable to purge a particulate filter at low engine loads because engine fuel consumption may have to be increased to purge the particulate filter. Therefore, it may be desirable to provide a way of extending an amount of time before the particulate filter is purged.
The inventors herein have recognized the above-mentioned disadvantages and have developed an engine fueling method, comprising: injecting fuel to a cylinder of an engine via a controller, a port fuel injector, and a direct fuel injector, the injection of fuel based on a group of pre-customer delivery control parameters, a group of post-customer delivery control parameters, the pre-customer delivery control parameters increasing an amount of port fuel injected as compared to the post-customer delivery control parameters during similar engine operating conditions.
By operating an engine with two different calibrations, it may be possible to provide the technical result of delaying purging of a particulate filter. For example, a fraction of port injected fuel may be increased and a fraction of directly injected fuel may be decreased for a cylinder cycle so that an engine produces less particulate matter as compared to if the engine were operating at the same engine speed and load with a lower port fuel injection fraction and a higher direct fuel injection fraction. Therefore, the particulate matter filter may be purged less often.
In one example, the port fuel injection fraction may be increased and a direct fuel injection fraction may be decreased when a vehicle is operated before being delivered to an end customer. The increased port injection fraction may allow the engine and vehicle to operate in an enclosed building for a longer amount of time before the particulate filter becomes filled. Once the vehicle is delivered to the end customer, the direct fuel injection fraction may be increased to leverage improved cylinder charge cooling because there may be more opportunities to purge the particulate filter without consuming higher amounts of fuel.
The present description may provide several advantages. For example, the approach may extend time between particulate filter purging. Additionally, the approach may reduce particulate formation within an engine. Further, the approach may be invoked for selected driving conditions where its benefits may be most useful.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.